Adjustable switching apparatus



Nov. 25,1969 E..c. WALKER ADJUSTABLE SWITCHING APPARATUS 6 Sheets-Sheet2 Filed June 30, 1965 INVENTOR. C. Walker FIG. 2s

Emil

@W i w A Nov. 25, 1969 E. c. WALKER ADJUSTABLE SWITCHING APPARATUS FiledJune 30, 1965 IOI 57 95 97 9 95 78 6 Sheets-Sheet 3 rney Nov. 25, 1969E. WALKER ADJUSTABLE SWITCHING APPARATUS 6 SheetsSheet 5 Filed June 30,1965 INVENTOR. Emil C. Walker BY K 4.9 Afiorney Nov. 25, 1969 E. c.WALKER 3,480,726

ADJUSTABLE SWITCHING APPARATUS Filed June 30, 1965 6 Sheets-Sheet 50FIG. 14

INVENTOR. EmiI C. Walker A'Horney United States Patent 3,480,726ADJUSTABLE SWITCHING APPARATUS Emil C. Walker, Woodstock, Ill., assignorto Zenith Radio Corporation, Chicago, 11]., a corporation of DelawareFiled June 30, 1965, Ser. No. 468,484 Int. Cl. H04n 1/44; G06k 7/00;H0111 43/08 US. Cl. 1785.1 12 Claims ABSTRACT OF THE DISCLOSURE Two setsof switch contacts may be permutably interconnected by having one of thesets take the form of a series of parallel, spaced apart metallic sliprings mounted on a rotor or drum, each ring having a multiplicity ofnotches. The other set of contacts includes a multiplicity of bearingballs held by a stator assembly and arranged in a series of parallelcolumns extending across the rows formed by the slip rings. The bearingballs of each column are disposed in alignment with and are spring urgedtoward assigned respective ones of the notches. A perforated code cardmay be moved from one to another of several different positions and ineach position interposes a different and unique pattern of perforationsbetween the bearing balls and notches to permit only predetermined onesof the bearing balls to engage their assigned notches through theperforations and permutably connect the two sets of contacts.

This invention relates to adjustable switching apparatus for permutablyconnecting one set of switch contacts to another set of switch contactsthrough a selected pattern of perforations in an insulating strip whichseparates the two sets of contacts. The invention is particularly usefulin a subscription television receiver of the type including anadjustable switching mechanism which must be adjusted by the subscriberin a particular prescribed manner for each program; hence, the inventionwill be described in that environment.

Switching arrangements have been developed in which a perforated stripor tape, adapted to be moved longitudinally from one to another ofseveral distinct positions, is interposed between two different sets ofswitch contacts to effect an interconnection pattern from one set to theother as determined by the particular perforations presented to thecontacts at the time. These prior systems are relatively expensive,however, and at times are not reliable. The novel switching apparatus ofthe present invention exhibits economy and reliability advantages overthe previous switching mechanisms.

It is therefore an object of the present invention to provide a new andimproved switching apparatus.

It is another object to provide a novel adjustable switching apparatuswhich is particularly useful in a subscription television receiver.

A switching apparatus, constructed in accordance with one aspect of theinvention, comprises a first set of switch contacts, each having aplurality of notches, arranged in rows. There is a second set of switchcontacts, each having a plurality of aligned bearing balls springs urgedtoward assigned respective ones of the notches, arranged in columns. Amultiposition, perforated insulating strip is adjustably supportedbetween the first and second sets of contacts and in each position thestrip interposes a predetermined pattern of perforations between thebearing balls and the notches to permit only predetermined ones of thebearing balls to engage their assigned notches through the perforationsand permutably connect the first and second sets of switch contacts. Theswitching apparatus also includes means for selectively moving the strip3,480,726 Patented Nov. 25, 1969 from one position to another to changethe permutation pattern between the first and second sets of contacts.

The features of this invention which are believed to be new are setforth with particularity in the appended claims. The invention, togetherwith further objects and advantages thereof, may best be understood,however, by reference to the following description in conjunction withthe accompanying drawings in which:

FIGURE 1 schematically illustrates in block diagram form a subscriptiontelevision receiver which includes a switching apparatus embodying theinvention;

FIGURES 2-13 are various detailed views of portions of the receiver ofFIGURE 1; and

FIGURES 14-17 depict modifications of the apparatus of FIGURES 2-13.

A subscription television transmitter for producing a coded televisionsignal of the type to be utilized by the receiver of FIGURE 1 is shownin detail in copending patent application Ser, No. 169,812, filed Jan.30, 1962, in the name of George V. Morris, and issued Apr. 5, 1966 asPatent 3,244,806, and assigned to the present assignee. Reference ismade to the Morris case for details of the transmitter. Very briefly, inthe transmitter the video signal is coded, that is to say, switched atrandom from one mode in which the video is delayed with respect to syncto another mode wherein video is transmitted normally or without delay.The mode changes in response to the amplitude variations of arectangular shaped coding signal developed by mode-determining circuitryand the instants at which the amplitude changes and, therefore, the modechanges occur are determined in part by the particular adjustment of anadjustable switching apparatus. That apparatus serves to permutablyapply a series of random code signal components to a plurality of inputcircuits of the mode-determining circuitry and a different adjustmentpreferably will be employed for each subscription telecast or program tothe end that each program is characterized by a unique coding schedule.

The receiver, shown schematically in FIGURE 1, is illustrated in detailin the aforesaid Morris application and reference may be made theretofor a more thorough explanation. FIGURE 1 is adequate, however, tounderstand the manner in which the switching apparatus of the presentinvention functions in conjunction with a subscription televisionreceiver.

In FIGURE 1, a cascaded arrangement of a radio frequency amplifier, afirst detector or oscillator-mixer, an intermediate frequency amplifierof one or more stages, a second or video detector, and a first videoamplifier is represented in a single block having input terminalsconnected to a receiving antenna 11 and output terminals coupled througha video decoder 14 to input terminals of a second video amplifier which,in turn, is connected to the input of an image-reproducing device orpicture tube. For convenience, the second video amplifier and imagereproducer are represented in a single block 15. Video decoder 14 may beidentical in construction to the video coder employed in the transmitterand includes a time delay network and an electronic switch having twooperating conditions. In one condition, the delay network is interposedin the video channel to delay the video with respect to the syncinformation, and in the other condition the delay network is removedfrom the video channel so that the video is translated through thedecoder Without the introduction of any significant time delay.

An output of the first video amplifier in block 10 is coupled to asynchronizing signal separator which energizes the usual field-sweep andline-sweep systems that are connected, in turn, to the deflectionelements associated with the picture tube in block 15. For convenience,the sync operator, and the fieldand line-sweep systems have been shownby a single block 17.

The audio circuitry of the receiver has not been shown in FIGURE 1 sincethat circuitry is not necessary to illustrate the operation of thepresent invention.

The random code signal components referred to above, developed in thetransmitter and employed to code the video signal, take the form ofsignal bursts occurring during vertical retrace and exhibiting at randomany one of five different frequencies from a group of six frequenciesdesignated f f The sixth frequency of the group is used for correlationtesting, a concept to be briefly described subsequently. It should benoted in passing that the frequency assigned to correlation testing maychange from one program to the next. In order to control the decodingapparatus at the receiver the code signal bursts as well as thecorrelation signal bursts are added to the composite video signal in thetransmitter during the verticalretrace intervals. Separating, filteringand rectifying circuitry, shown by block 19, has an input coupled to theoutput of the first video amplifier in block and produces from thecomposite video signal during each field-retrace interval rectifiedbursts of frequencies f -f on respective ones of six different outputconductors 21-26.

The six output conductors 21-26 are respectively connected to six inputterminals of an adjustable code-determining switching apparatus orpermutation device which has a series of five output conductors 31-35.Switching apparatus 30, which embodies the present invention,corresponds in function to a switching apparatus of the transmitter andestablishes different prescribed ones of a multiplicity ofinterconnection patterns between input conductors 21-26 and outputconductors 31-35. Structurally the apparatus may comprise a family ofswitches the adjustment of which selects the desired permutation patternbetween input and output conductors for a given program interval. Apreferred form of switch is shown in detail in FIGURES 213, to bedescribed hereinafter. The transmitter switching apparatus may beidentical.

Switching apparatus 30 permutes the applied code signal bursts asrequired before they are used for decoding the video signal andgenerally it will have to be adjusted differently for each subscriptionprogram to be viewed.

It will be observed that output conductor 31 of switching apparatus 30is connected to ground; hence, any code signal components emerging onoutput 31 are eliminated and serve no function. Output conductors 32-34,on the other hand, are connected to respective ones of a series of threeinput circuits of a unit referred to as the modedetermining circuitryand which corresponds in construction to the transmittermode-determining circuitry. Unit 40 has another input circuit connectedto the line-sweep system of block 17 to receive line-drive pulsesthereover and it further includes a counting mechanism provided by a 7:1blocking oscillator having an output connected to a bi-stablemultivibrator. The blocking oscillator is driven by the line-drivepulses and the output of the multivibrator is connected to theelectronic switch in video decoder 14. Mode-determining circuitry 40,counting mechanism in response to the line-drive pulses, produces forapplication to the video decoder a control or decoding signal ofrectangular waveshape having an amplitude change occurring after everyseven line traces. Since the code signal components applied to unit 40via conductors 3234 occur at random during each field-retrace interval,the periodic actuation of the mode-determining circuitry under theinfluence of line-drive pulses is interrupted during each verticalretrace by these code signal components. .The effect of the code signalcomponents is to determine the phase of the decoding signal duringvertical retrace.

A correlation testing arrangement is provided to effectively examine theinstantaneous adjustment of apparatus 30 and determine if it iscorrectly adjusted for any given program. Specifically, output conductor35 of switching apparatus 30 is connected to one input of a unit 44referred to as the correlation testing circuitry. Another input of unit44 connects to the output terminal of modedetermining circuitry 40. Asmentioned previously, for any given program one of the available codefrequencies f f is selected at the transmitter for correlation testing.For convenience, it will be assumed that code signal bursts of frequencyf are chosen for that purpose. If the setting of switching apparatus 30'agrees with the setting of the corresponding switching apparatus at thetransmitter, the code signal bursts of frequency f will be applied tocorrelation testing circuitry 44. Unit 44 includes a comparator, such asa gate circuit, to which is supplied the correlation code signalcomponents from switching apparatus 30 and from mode-determiningcircuitry 40 a locally-generated comparison signal which represents theactual setting of the switching apparatus 30.

To explain, one correlation code signal component of frequency 13 occursat the transmitter during each fieldretrace interval and at a time whenthe bi-stable multivibrator in the transmitter mode-determiningcircuitry is established in a predetermined one of its two conditions.As a consequence, the correlation code signal components represent thesetting of the adjustable switching apparatus of the transmitter andthey are transmitted to the subscriber receivers for comparison purposesto check the adjustment of the switching apparatus at each receiver.Since the waveshape of the decoding signal produced by the receivermode-determining circuitry 40 is influenced by switching apparatus 30,that waveshape represents the instantaneous setting of the switchingapparatus. Correlation testing circuitry 44 compares the waveshape ofthe decoding signal with the series of correlation code signalcomponents received from the transmitter. If the receiver switchingapparatus is properly set up, the timing of the correlation code signalcomponents will exhibit a predetermined relation with respect to therectangular waveshape of the decoding signal and provide an indicationof correct correlation.

More specifically, for a properly adjusted receiver there will bedeveloped, at the output of the comparator in correlation testingcircuitry 44, one pulse during each field-retrace interval. When thereis an uninterrupted series of these pulses throughout a ten-secondtesting interval, a control effect is produced which confirms a correctsetting of adjustable switching apparatus 30. This is achieved in theaforesaid Morris case by means of a mechanical timing device which, inresponse to the uninterrupted series of pulses, closes a set of switchcontacts.

An output of testing circuitry 44 is connected toa charge register 46 toeffect actuation thereof when correct correlation has been confirmed. Toelucidate, the switch contacts controlled by the timing device areincluded in the energizing circuit for a charge solenoid which forms apart of charge register 46. When correct correlation exists between thesetting of switching apparatus 30 and the setting of the counterpartswitching apparatus at the transmitter, the switch contacts controlledby the timing mechanism are closed to complete the energizing circuitfor the charge solenoid. The charge register in Morris prints a chargeon a paper billing tape and its solenoid is therefore referred to as aprint solenoid. The manner of making, and the nature of, the recordedcharges will be described in connection with FIGURES 2-17.

Preliminarily, a brief review will be given of the operation of thereceiver of FIGURE 1. A television signal, which has been coded at thetransmitter by delaying certain time segments of video information, isintercepted by antenna 11, amplified in the radio frequency amplifierand heterodyned to the selected intermediate frequency of the receiverin the first detector. The intermediate frequency amplifier and detectedin the second detector to produce a coded composite video signal whichis then amplified in the first video amplifier. The amplified video istranslated through the cascade arrangement of video decoder 14 and thesecond video amplifier to the input electrodes of the picture tube inunit '15 to control the intensity of the cathode ray beam thereof inconventional manner. The sweep systems in unit 17 are controlled inconventional manner by the synchronizing signal separator.

Unit 19 separates and rectifies the random code and correlation signalcomponents from the composite video signal and applies these componentsto input conductors 21-26 of switching apparatus 30, the particularadjustment of which determines the permutation routing of thosecomponents to output conductors 31-35. Assuming that switching apparatusin the receiver effects the same permutation as the counterpartswitching apparatus in the transmitter, the correct code components willbe channeled to the bi-stable multivibrator in mode-determiningcircuitry 40. That multivibrator, which is periodically actuated by theoutput of the line-drive pulse driven 7:1 blocking oscillator, istriggered by the random code signal components in exact synchronism withthe actuation of the corresponding multivibrator in the transmitter.

The rectangular shaped decoding signal, produced in the output of thereceiver mode-determining circuitry, thus has a waveform which isidentical to that of the coding signal in the transmitter. Theelectronic switch in decoder 14 will therefore be actuated by thedecoding signal in time synchronism with the counterpart electronicswitch in the transmitter code which is necessary to decode the receivedsignal.

Since the receiver switching apparatus is properly set up, thecorrelation code signal components of frequency 3 applied to correlationtesting circuitry 44 will exhibit the required relationship with respectto the waveform of the decoding signal developed by unit and applied tounit 44. A control effect, in the form of closing of switch contacts tocomplete the energizing circuit for the charge solenoid in chargeregister 46, will thus be produced with the result that the solenoidwill be actuated to effect registration of a charge in the manner to bedescribed.

Directing attention to FIGURES 2-13, and particularly to FIGURE 2, allof the circuitry and equipment required to convert a conventionaltelevision receiver to a subscription television receiver is housedwithin a metal cabinet 50. Preferably, cabinet is mounted on top of orin close proximity to the television receiver and a cable (not shown)provides the necessary circuit connections therebetween.

A control knob 52, see especially FIGURES 2 and 4, positioned on thefront of cabinet 50 is connected to an operating shaft (not shown) whichoperates a PV-TV switch. Knob 52 is to be manipulated by the subscriberto the PV position for the reception of a subscription televisionprogram and to TV when the decoding apparatus is to be effectivelydisassociated from the television receiver. The indicia PV is ashorthand designation of the assignees Phonevision subscriptiontelevision system. Positioned on the side of cabinet 50 exposed inFIGURE 2 is a manual control knob 54 which must be adjusted by thesubscriber to establish switching apparatus 30 in the required conditionof adjustment for any given program. Cabinet 50 has a display window inthe form of a magnifying viewing lens 55, see especially FIGURE 3.

The establishment of different switching conditions to achieve differentinterconnection patterns between input conductors 21-26 and outputconductors 31-35 of switching apparatus 30 is facilitated by aperforated, flexible insulating strip, such as a card 57 (see especiallyFIG- URES 2, 3 and 8), which is threaded through sensing or readingequipment within cabinet 50, being fed into the cabinet through inputslot 58 and emerging by way of exit slot 59. Perforated or punched card57, which may be called a code-bearing element for reasons which will beapparent, has a series of thirty-one distinct operating positions withrespect to the reading apparatus and, in a manner to be explained, istransported in step-by-step fashion from one position to the next byrotation of control knob 54. In each of the thirty-one differentpositions, a unique pattern of perforations 61, in the left half ofstrip 57 as viewed in FIGURE 8, is interposed between input switch orsensing contacts, connected to input conductors 21-26, and output switchor sensing contacts connected to output conductors 31-35. Each patternof perforations permutably connects the input to the output switchcontacts in accordance with a different intercon nection pattern. Thethirty-one different numbers (101- 131) displayed or printed along theleft margin of strip 57 (FIGURE 8) may be referred to as code numbersand are employed to facilitate the selection of the correct pattern ofperforations required for each different pro gram. For any givenprogram, knob 54 is rotated by the subscriber until a prescribed one ofthe code numbers 101-131 on card 57 is exposed through window 55. Asshown in FIGURE 2, the code number 121 is revealed and this indicatesthat the perforation pattern associated with that number is effective,namely is interposed between the input and output switch contacts.

Referring now to the details of the switching apparatus itself, cabinet50 has a base 63 (see especially FIG- URE 4) to which is rigidly mounteda pair of spacedapart upright supports 64 and 65, which are parallel toeach other as well as to the side walls of cabinet 50. The centralportion of each of support members 64 and 65 is apertured and providedwith a sleeve type bearing 66, the bearings being aligned and rigidlymounted to their associated support members. Journalled within bearings66 is an operating shaft 68, the right end of which (as viewed in FIGURE4) is rigidly aflixed to transport knob 54. This may conveniently beachieved by providing the right end of shaft 68 with a fiat and knob 54with a D-shaped hole to receive the shaft. A pair of C-shaped retainingrings 69 are mounted in grooves of shaft 68 to captivate the shaft withrespect to axial movement in support members 64 and 65. The groovesaround shaft 68 which accommodate retaining rings 69 are visible in FIG-URE 10 and are designated by the reference numerals 71.

Switching apparatus 30 includes a rotor or drum assembly (see especiallyFIGURES 4 and 10) which is rigidly mounted to shaft 68 between supports64 and 65 and rotates in response to manipulation of knob 54. Morespecifically, the rotor assembly includes a core element 73, constructedof some appropriate insulating material such as plastic, that is fixedlyconnected to shaft 68 by the expedient of providing shaft 68 with a flatand the core with a channel, through which the shaft extends, of matingor complementary D-shaped cross section. This is best seen in the crosssectional view of FIGURE 11. The right half of core member 73 (as viewedin FIGURE 4) is hollowed out to reduce the weight of the drum assembly.The hollowed out portion thus essentially constitutes a cylindricalshaped section, the external surface of which is provided with a seriesof equally spaced grooves 75 (see especially FIGURES l0 and 12) thatextend in a direction parallel to the axis of shaft 68. The purpose ofgrooves 75 will be explained later.

The left half of core 73 (as viewed in FIGURE 4) merely constitutes abase to provide a support for other elements of the rotor assembly.Initially, the left section of core 73 supports a metallic circular disc77 which is apertured to fit over the core. Disc 77 is fixedly mountedand indexed to core 73 by the expedient of a flat on the core (seeFIGURE 11) and a mating D-shaped configuration of the aperture in thedisc. The entire circumference of metallic disc 77 is provided with aseries of regularly spaced teeth 78 (see especially FIGURES 10 and 12)which constitute sprocket teeth of appropriate dimensions to beaccommodated by regularly spaced sprocket holes 79 in removable card 57,see FIGURE 8. The expedient of providing disc 77 with an aperture thatmates with the core 73 in only one relative position of the core anddisc results in automatic indexing of the sprocket teeth 78 with respectto grooves 75 and to the other elements of the rotor assembly to bediscussed as the rotor assembly is manufactured.

There is also rigidly mounted and indexed to the left section of core 73a series of five parallel metallic electrically conductive discs or sliprings 81 which are spaced apart from each other and also from sprocketdisc 77 by means of a series of five insulating spacers 83. Each of thefive discs 81 and the five spacers 83 is provided with a D-shapedaperture which corresponds to the crosssectional configuration of theleft section of core 73 in order that all of those elements may beindexed with respect to sprocket disc 77.

The periphery of each disc 81 has a thickness approximately double thatof the remainder of the disc, see FIGURE 4. The peripheries of discs 81therefore eifectively provide a series of five similarly shaped sliprings; hence discs 81 are also referred to as slip rings. Each ring isprovided, around its entire circumference, with a series of equallyspaced notches 84 (see especially FIG- URES 10, 11 and 13), and sliprings 81 are so positioned with respect to each other that the notchesof each ring are aligned with corresponding notches of the other ringsand in a direction parallel to the axis of the rotor assembly. Forreasons which will become apparent, slip rings 81 provide conductive busbars.

To the left of discs 81 and 77 and spacers 83 (as viewed in FIGURE 4) isa retaining disc 86, constructed of insulating material such as plastic,which is apertured to fit over the left section of core 73. A metallicwasher 88 and a nut 89 are provided to hold the various elements of therotor assembly together. The extreme left end of core 73 is threaded toaccommodate nut 89.

Adjustable switching apparatus also includes a fixed stator assembly(shown by itself in FIGURE 9) which has a main support or base member93, constructed of some suitable insulating material such as plastic,that is rigidly aflixed to upright supports 64 and 65, see FIG- URE 4. Aseries of thirty cylindrical shaped channels 95, arranged in rows andcolumns, five rows with six per row and six columns with five percolumn, as best seen in FIGURE 9 are formed in stator support 93. Eachchannel 95 extends throughout the entire thickness of stator support 93in a direction perpendicular to the axis of the rotor assembly, as bestseen in FIGURES 3, 4 and 13. The six aligned channels 95 of each rowextend along an arc of the stator assembly, and the five alignedchannels 95 of each column extend along a straight line parallel to theaxis of the rotor assembly. The channels are so dimensioned andpositioned that the distance between centers of adjacent channels ineach row equals the distance between centers of adjacent notches 84 ineach of slip rings 81, as best seen in FIGURE 13. The five rows ofchannels 95 are also positioned so that each row extends along or linesup with a respective assigned one of the slip rings.

The rotor assembly may be provided with a detent device (not shown)which insures that the rotor assumes distinct and predetermined indexedpositions when it is rotated in response to rotation of knob 54. Each ofthese positions would be indexed with respect to channels 95 in orderthat the channels will register or be in juxtaposition with respectiveones of notches 84 (see FIGURE 13) in every discrete position of therotor assembly.

Each channel 95 contains, at its end closest to the rotor assembly, ametallic conductive floating bearing ball 97 on top of which is aninverted metallic eyelet or thimble 98, see FIGURE 13. An electricallyconductive coil spring 99 is positioned on top of thimble 98 in each ofthe thirty channels 95. The bearing balls, eyelets and coil springs mayall be suitably plated for maximum electrical conductivity. The fivecoil springs 99 contained in the five channels 95 forming each of thesix columns are electrically connected to an assigned one of a group ofconductive bus bars 101 rigidly aflixed to stator support 93. Inmanufacturing the switching apparatus, each spring 99 is compressed sothat a constant force is exerted against the associated bearing ball 97.In this way, each bearing ball is spring urged downward toward a notch84 of one of slip rings 81.

The six bus bars 101 are respectively electrically connected, such as bysoldering, to the six input conductors 21-26 of the switching apparatus.With this arrangement, each of input conductors 21-26 is electricallyconnected to an assigned group of five bearing balls 97.

Stator support 93 also includes a series of five cylindrical shapedchannels 106 (see especially FIGURES 3 and 9) which extend therethroughin a direction perpendicular to the axis of the rotor assembly. Channels106 are staggered and spaced so that they register with respective onesof the five slip rings 81. In other words, each of the five channels 106lies on the same arc defined by a respective one of the five rows ofchannels 95. As in the case of channels 95, each channel 106 alsoincludes a compressed coil spring 107 and a metallic conductive bearingball 108, as shown in FIGURE 3. It is also contemplated that invertedeyelets or thimbles, similar to thimbles 98, will be positioned betweensprings 107 and bearing balls 108. Channels 106 are also positioned,with respect to channels 95, such that when channels 95 are injuxtaposition or register with respective notches 84 of slip rings 81channels 106 will likewise register with respective ones of notches 84.

A series of five parallel metallic conductive bus bars 111, rigidlymounted to stator support 93, cover respective ones of the five openings106 and extend in a direction parallel to the axis of the rotorassembly. The five coil springs 107 are electrically connected torespective ones of the five bus bars 111 and the output conductors 31-35of adjustable switching apparatus 30 are electrically connected, such asby soldering, to respective ones of the five bus bars 111. With thisarrangement, each of output conductors 31-35 is electrically connectedto a respective one of the five bearing balls 108.

Input conductors 21-26 and bearing balls 97 are connected to slip rings81 and thence to hearing balls 108 and output conductors 31-35 inaccordance with different permutation or interconnection patterns bymeans of removable code card 57. Stator support 93 is provided with aslot 114 that registers with slot 58 of cabinet 50, see FIGURES 2, 3 and9. The subscriber is obliged to insert code card 57 into slots 58 and114 with the top edge of the card, as viewed in FIGURE 8, insertedfirst. Card 57 may be moved without opposition until it engages one ofsprocket teeth 78. Further movement of the card can be achieved only byclockwise rotation of knob 54, as viewed in FIGURE 2. The entire rotorassembly rotates and sprocket teeth 78 engage holes 79 of card 57,moving it in a direction toward the rear of cabinet 50. A guide member116, preferably constructed of metal, is rigidly connected to statorsupport 93 and also to the bottom of cabinet in order to hold card 57 inengagement with the sprocket teeth and to guide it in a semi-circularpath with the result that the card emerges from cabinet 50 through exitslot 59.

As mentioned previously, it is contemplated that switching apparatus 30must be adjusted differently for each diiferent subscription program andcard 57 i capable of eifecting thirty-one different adjustments each ofwhich is indicated by a respective one of the code numbers 101- 131printed along the left margin of the card. The different code numbersrequired to decode different subscription programs will be publicized,such as in program booklets, newspaper listings, etc. Advance publicitymay also be given relative to the nature of and cost of each program.The subscriber must then initially ascertain the particular code numberfor a specified program in which he is interested. Stator support 93also has an aperture 118 that registers or coincides with window ofcabinet 50 and both of these openings are positioned such that thethirty-one code numbers on code card 57 are exposed one 9 at a time asthe card is transported from one position to the next by rotation ofknob 54.

The subscriber rotates knob 54 until the code number, assigned to theprogram he wishes to view, is exposed in window 55. Assume, for example,that to decode a given subscription telecast code number 121 must bedisplayed in window 55, as shown in FIGURE 2. When that occurs apredetermined pattern of perforations 61 registers with hearing balls97. The sprocket teeth 78 are also positioned with respect toperforations 61 such that the perforations will automatically registerwith assigned respective ones of notches 84 of slip rings 81. In thisway, when a code number is centered within window 55 each of theeffective perforations 61 will be interposed between and injuxtaposition with an assigned bearing ball 97 and an assigned notch 84.

Incidentally, it was mentioned previously that a detenting mechanism(not shown) may be incorporated in the switching apparatus to insurethat the rotor assembly is rotated in steps to the end that notches 84line up with the bearing balls. It will now be recognized that no detentapparatus is essential if the subscriber always makes certain that eachspecified code number is centered within window 55. Besides, detentingto some extent occurs by the action of the bearing balls being forcedinto the notches. If the rotor assembly is not precisely positioned, thebearing balls will automatically seat in the notches and in so doing therotor assembly is rotated slightly.

Since bearing balls 97 are spring urged toward slip rings 81, whenever aperforation 61 lies immediately beneath a bearing ball that ball ispermitted to drop into the notch 84 which is in register with thebearing ball at the time, as shown by the second or middle bearing ball97 in FIGURE 13. Of course, the diameter of each perforation 61 shouldexceed the width of each notch 84. Preferably, the diameter of eachbearing ball 97 is also greater than the width of each notch 84.Moreover, each notch preferably is provided with two relatively sharpedges or corners so that when a bearing ball engages a notch, theengagement takes place at two knive-edge contacts. The associated coilspring 99 produces a relatively high contact force along the knife-edgeor line contacts. In this way, the possibility of a faulty electricalconnection between a bearing ball 97 and a notch 84 through aperforation is virtually eliminated.

The thimble 98 insures that the force of spring 99 is even applied tothe bearing ball. In addition, the expedient of a thimble permits thebearing ball to float freely by preventing the lower end of theassociated spring 99 from being spread or pushed out by the bearing balland in so doing jamming itself against the internal surface of theassociated channel 95.

Of course, when there is no aperture 61 immediately beneath a bearingball 97, that ball is prevented from engaging the notch 84 with which itis lined up. This is the case illustrated by the first and third bearingballs shown in FIGURE 13.

It has thus been shown that certain ones only of the thirty bearingsballs 97 are electrically connected to their assigned slip rings 81 forthe assumed setting of knob 54 and since those bearing balls are in turnelectrically connected to associated ones of input conductors 21-26 ithas been shown that those conductors are permutably connected to thefive conductive bus bars or slip rings 81 in accordance with apermutation or interconnection pattern established by the particulargroup of perforations 61 interposed between the bearing balls and theslip rings. It is necessary to transfer the electrical connections fromslip rings 81 to output conductors 31-35. This is achieved by means ofthe five bearing balls 108 each of which is urged into a notch 84 of arespective one of the five bus bars 81. As shown in FIGURE 3, code card57 is threaded through the switching apparatus so that it is immediatelyadjacent to only approximately one-half of the rotor assembly. In thisway, the card is not interposed between bearing balls 108 and slip rings81. As a consequence, for each distinct position of card 57 and therotor assembly bearing balls 108 will register with and engage assignednotches 84 of the slip rings in the same manner as illustrated by themiddle bearing ball 97 in FIGURE 13.

The five slip rings 81 will therefore be electrically connected, by wayof the five bearing balls 108, their associated coil springs 107, andbus bars 111, to respective ones of output conductors 31-35. Each ofinput conductors 21-26 is thus permutably connected to at least one ofoutput conductors 31-35 via an associated bus bar 101, a coil spring 99,an inverted thimble 98, a bearing ball 97 which extends through aperforation 61 of code card 57, a notch 84 of one of the slip rings 81,the bearing ball 108 engaging that slip ring, the associated coil spring107 and bus bar 111 for that bearing ball 108 and thence to the selectedone of output conductors 31-35.

In rotating the rotor assembly from one discrete position to the next,all of the bearing balls 97 and 108 that have engaged notches 84 will beexpelled or forced upward against the tension of the associated coilspring by the unnotched portions of slip rings 81. In other words, theballs will be cammed out of the notches. To insure that switchingapparatus 30 does not jam and that the bearing balls may be readilyretracted from engagement with the notches, the notch width and diameterof the bearing balls are so proportioned and dimensioned that when abearing ball drops into and engages a notch its downward movement willbe limited by the edges of the notch to the extent that the center ofthe bearing ball will always lie above the notch, as shown by the middlebearing ball 97 in FIGURE 13. With this arrangement, the bearing ballmay be cammed upward with little ditficulty as the rotor assembly istransported from one position to the next.

While it is contemplated that successive subscription televisionprograms will require successively higher code numbers, which wouldnecessitate only clockwise rotation of knob 54 between programs, therotor assembly may obviously be rotated in either direction. Hence, if asubscriber inadvertently rotates transport knob 54 too far in aclockwise direction and passes up the code number required for a givenprogram, that code number may be reached merely by backing up the knobor rotating it in a counterclockwise direction.

To insure that bearing balls 97 do not tear or damage code card 57, thediameter of each perforation 61 preferably exceeds the diameter of eachbearing ball. This is also best seen by the middle bearing ball inFIGURE 13 and the associated perforation 61. Small areas of theunnotched portions of slip ring 81 adjacent the two sharp corners of anotch are exposed through each perforation 61. Each of these small areasis referred to as slot land. Since the edges of each perforation do notcoincide with the edges of a notch, the possibility of a bearing balldamaging the code card as the ball drops in or is expelled from thenotch is avoided.

To briefly summarize the illustrated switching apparatus, in accordancewith the present invention, the five slip rings 81 effectively provide afirst set of switch contacts, each having a plurality of notches 84,arranged in rows. Elements 101, 99, 98 and 97 effectively provide asecond set of switch contacts, each having a plurality of alignedbearing balls 97 spring urged toward assigned respective ones of notches84, arranged in columns. Code card 57 constitutes a multi-position,perforated insulating strip separating the first and second sets ofcontacts and in each position interposing a different and unique patternof perforations between the bearing balls 97 and notches 84 to permitonly predetermined ones of the bearing balls to engage their assignednotches through the perforations thereby to permuta'bly connect thefirst and second sets of switch contacts. The rotor assembly, includingtransport knob 54, provides means for moving strip 57 from one positionto another to change the permutation pattern between the first andsecond sets of contacts. The first set of contacts 81 are electricallyconnected to output conductors 31-35 via bearing balls 108, springs 107and bus bars 111, while the second set of contacts are directlyconnected to input conductors 21-26.

Attention will now be directed to the charge register or recordingequipment contained within cabinet 50. A fixed support bracket 121 witha U-shaped cross-section has its bight portion rigidly affixed to thebottom of cabinet 50, see FIGURE 6. Another fixed support bracket 124 isrigidly mounted to and between the upright portions of bracket 121.Slideably mounted to bracket 124 is a slide bracket or carrier 126, bestseen in FIGURE 7. Such a mounting arrangement is facilitated by a pairof guide studs 127, rigidly mounted to fixed bracket 124, whichrespectively ride in a pair of guide slots 128 in slide bracket 126.Captivation of bracket 126 is obtained by C-shaped retaining rings 129mounted in grooves of studs 127 on top of the bracket. Bracket 126 maythus be moved in a horizontal direction, as viewed in FIGURES 3 and 5.

Slide bracket 126 has a pair of upright portions which are apertured toreceive a shaft 131. Rigidly afiixed to shaft 131, between the uprightportions, is a series of live cam or notched discs 132. The periphery ofeach disc 132 is broken up into a series of irregularly spaced notchesof varying width. Hence, the radius of each cam disc has one of twodifferent values depending on where on the circumference the measurementis made. Shaft 131 extends beyond the right upright portion of slidebracket 126 (as viewed in FIGURE 6) and accommodates a ratchet 134 whichis rigidly affixed to the shaft with respect to rotational movementthereof. In other words, ratchet 134 is so positioned on shaft 131 thatrotational movement of the ratchet effects concurrent rotation of theshaft.

A pair of C-shaped retaining rings 135 are mounted in grooves providedin shaft 131 to captivate cam discs 132 and ratchet 134 against movementin the direction of the axis of the shaft. As viewed in FIGURE 6, oneretaining ring 135 is mounted immediately to the left of the leftupright portion of bracket 126 while the other ring 135 is mountedimmediately to the right of ratchet 134. Slide bracket 126 has adepending tab 137 (best seen in FIGURE 6) to which is rigidly mountedone end of a flexible, fiat spring arresting pawl 138, the other end ofwhich is free and positioned to engage a tooth of ratchet 134. Pawl 138holds ratchet 134 against any counterclockwise movement, as viewed inFIGURE 3.

The portion of fixed support bracket 124 closest to the right uprightportion of bracket 121 (as viewed in FIGURE 6) has a series of rightangle bends and is of U-shaped cross-section to accommodate a shaft 141which is journalled in and mounted between two apertures provided inbracket 124. This shaft is likewise captivated against axial movement bya pair of C-shaped retaining rings 142. A drive pawl 143 is rotatablymounted on shaft 141 within the U-shaped portion of bracket 124 and ispositioned to engage the teeth of ratchet 134. A wire spring 146, whichis coiled around shaft 141, has one of its ends hooked around pawl 143and its other end hooked on bracket 124 in order to exert a clockwisetorque, as viewed in FIGURES 3 and 5, on pawl 143. In this way, pawl 143is urged into engagement with periphery of ratchet 134.

A solenoid 149, which constitutes the charge solenoid discussedhereinbefore, is fixedly mounted by means of a bracket 151 to the bightportion of the U-shaped support bracket 121. Conductors 152, attached tothe charge solenoid, are connected to an energizing circuit fu-llydescribed in the copending Morris case, Ser. No. 169,812. Slide bracket126 has a depending arm 153 which is attached to the plunger 154 ofsolenoid 149. A coil spring 155, connected between arm 153 and adepending arm 157 of fixed bracket 124, biases slide bracket 126, and

12 the elements 131-138 mounted thereon as well as plunger 154, towardthe left as viewed in FIGURE 3. That figure illustrates the relativepositions of fixed bracket 124 and movable bracket 126 when solenoid 149is de-energized.

In response to energization of the solenoid, plunger 154 is pulled tothe right. Arm 153 is attached to plunger 154 in such a manner thataxial movement of the plunger results in movement of arm 153 and slidebracket 126. FIGURE 5 shows the relative positions of brackets 124 and126 when solenoid 149 is activated.

The upright portions of fixed bracket 121 are also provided with a pairof aligned apertures to accommodate and support a shaft 159, best seenin FIGURE 6. A pair of C-shaped snap washers 161 are respectivelymounted in grooves of shaft 159 to captivate shaft 159 between the twoupright portions of bracket 121. A series of five bellcranks 162 arerotatably mounted on shaft 159 for independent movement. A spring member163 is aflixed to bracket 121 and engages each of the five bellcranks162 in order to bias them with a clockwise torque, as viewed in FIGURE3. A stop pin 164, rigidly mounted to and between the upright sectionsof bracket 121, limits the clockwise movement of each bellcrank by thepressure of spring 163.

Each of the five bellcranks 162 is provided with an extending sensing orcam follower tab 167 and, as seen in FIGURE 6, is aligned with arespective one of the five cam discs 132. The sensing tab 167 on eachbellcrank is so positioned that it senses the presence or absence of anotch on its assigned cam disc 132 in response to energization ofsolenoid 149, as will be explained.

An aperture is provided at the end of each bellcrank 162 to accommodatea lancing or piercing pin 169. A pair of collars 171 are mounted on eachpin 169 to captivate the pin to the associated bellcrank while stillpermitting limited relative movement between the pin and bellcrank. Eachof the five lancing pins 169 extends into and slides within an assignedone of five cylindrical guide channels 172 (see FIGURE 9) formed instator support 93. The diameter of each channel 172 is made slightlylarger than the diameter of each pin 169 to permit .slideable movementof the pins with respect to their associated guide channels. Pins 169and channels 172 are so positioned that when the rotor assembly isindexed in any one of its discrete positions, a slot of the rotor core73 registers with or lies below each of the five aligned pins 169. Asshown in FIGURE 3, the length of each lancing pin 169 is such that itspointed end lies slightly above and out of engagement with code-bearingcard 57.

Consideration will now be given to the operation of the charge register.Assume that a particular subscription telecast which the subscriberdesires to view requires the pattern of apertures 61 designated by thecode number 101 to achieve decoding and intelligible reproduction. Thesubscriber rotates transport knob 54 until the code number 101 appearsin window 55. As briefly explained previously and in detail in thecopending Morris case Ser. No. 169,812, a series of correlation testsduring a tensecond interval are performed to determine whether switchingapparatus 30 is appropriately adjusted for the program in question,namely to determine if the correct pattern of apertures 61 has beenselected to permute input conductors 21-26 to output conductors 31-35.

Since it has been assumed that the subscriber has employed the correctcode number, the correlation tests will indicate correct correlation, asa result of which the energizing circuit for charge solenoid 149 will becompleted and the solenoid will actuate. In so doing, plunger 154 movesto the right (as viewed in FIGURE 3) against the tension of springcausing slide bracket 126 to move toward the position shown in FIGURE 5.Inasmuch as the position of shaft 131 is fixed with respect to bracket126, such movement of the bracket effects movement of shaft 131, ratchet134 and cam discs 132 to the right.

However, since drive pawl 143 is mounted to fixed bracket 124, movementof ratchet 134 toward the right causes a slight clockwise rotation ofthe ratchet which in turn causes concurrent rotation of all of discs 132which move in unison. For reasons to become apparent, ratchet 134 shouldpreferably have thirty-one teeth in order that discs 132 rotate only ofa complete revolution. A different portion of the periphery of each camdisc 132 will now be adjacent the sensing tab 167 of the associatedbellcrank 162.

As slide bracket 126 continues to move toward the right those discs 132having unnotched or raised portions adjacent their associated sensingtabs 167 engage those tabs and effect counterclockwise rotation of theassociated bellcranks 162 against the tension of spring 163. The lancingpin 169 attached to each actuated bellcrank is pushed toward the axis ofthe rotor assembly to the extent that the pin pierces a hole in card 57.This, of course, is best seen in FIGURE 5. Slots 75 are provided, ofcourse, to receive those lancing pins 169 that are pushed through card57.

It will be assumed that in the illustrated case only two of the fivecams 132 engage their associated bellcranks with raised or unnotchedsections. Hence, only two apertures are punched in card 57. It willfurther be assumed that the two actuated bellcranks 162 include the oneshown on the extreme right and the second one from the left, as viewedin FIGURE 6. The piercing pins 169 associated with those two bellcrankswill hence produce perforations 175 in the right half of card 57, asviewed in FIGURE 8. Since the position of holes 175 with respect to thelength dimension of card 57 is determined by the code number displayedin window 55, that particular position is indicative of the pattern ofperforations 61 employed for a given program, which pattern is unique tothat program. Thus, apertures 175 indicate the identity of the programto which the subscriber has subscribed.

Apertures 175, however, represent more than merely the identity of aprogram. They represent a charge sequence number in binary notation.Specifically, since there are five discs 132, the periphery of each ofwhich may -be either notched or un-notched at any given point, thecombination of the five discs facilitates the representation ofthirty-one different numbers 1-31. Restricting the incremental steprotation of discs 132 to of 360 permits the discs to have thirty-onedifferent positions each of which provides a representation of anassigned respective one of charge sequence numbers 1-31. An unnotchedsection of a disc 132 represents one in binary notation, while a notchedportion represents a zero. Hence, since perforations 175 are produced byunnotched sections, they represent ones. The absence of two holesbetween apertures 175 and the absence of a hole immediately to the leftof the left-most punch 175 represent zeros. Thus, the charge registeredby the two apertures 175 represent the binary number 01001 whose decimalequivalent is 9.

De-energization of solenoid 149 permits coil spring 155 to move slidebracket 126 back to its home position as illustrated in FIGURE 3. Duringthat movement, ratchet 134 moves to the left with respect to drive pawl143 which is cammed out of engagement with one ratchet tooth and intoengagement with the next adjacent tooth. Arresting pawl 138 preventsratchet 134 from rotating counterclockwise.

Assume now that the next program to which the subscriber subscribes isthat requiring the pattern of apertures 61 associated with code number102. When knot 54 is rotated to display code number 102 the decodingapparatus functions to decode the telecast and charge solenoid 149actuates. Slide 126 once again moves toward the right and all of discs132 rotate clockwise one step (%1 of 360) in unison. The discs are soshaped that the portions of their peripheries adjacent sensing arms 167of bellcranks 162 represent the binary number 01010, the

14 decimal equivalent of which is 10. Hence, the two perforations 176will be punched in the right half of card 57.

The next program viewed by the subscriber requires the perforations 61associated with code number 107. Again solenoid 149 energizes andeffects rotation of discs 132 one step and the piercing of holes in card57 which reflect the peripheries of the discs being sensed by tabs 167.The configurations of the discs will be such that the third programviewed results in the piercing of the three perforations 177 indicativeof the binary number 01011 or decimal number 11.

As revealed in FIGURE 8, six subsequent programs are subscribed toresulting in the registration of charges that represent in successiondecimal numbers 12-17.

The nine separate charges recorded on card 57 thus not only reflect theidentity of nine separate programs viewed by the subscriber but anunbroken sequence of nine charge numbers 9-17. When the card is turnedin to the subscription television operating company a bill may beprepared based on the charges recorded on the code card. Moreover, tomake certain that the subscriber has not employed a counterfeit orbootleg card to achieve the necessary interconnection pattern inswitching apparatus 30 to view some programs, which card would serve asthe recording medium to register the charges, the operating company cancheck the recorded charge sequence numbers, on the authorized cardturned in, to determine if they all follow in proper sequence.Incidentally, while in the illustrated case the charge numbers follow aregular consecutive sequence, obviously this is not necessary since thenumbers may follow any predetermined random pattern.

To more fully understand the manner in which any illicit activity on thepart of the subscriber may be detected, assume that the subscriberemploys a counterfeit card for some or all of the programs during theperiod covered by the code card which is to be employed subsequent tothe one shown in FIGURE 8. Since the last charge number recorded on card57 in FIGURE 8 is number 17, charge sequence numbers starting at 18 willbe recorded on the unauthorized card. Of course, after charge sequencenumber 31 is registered cam discs 132 cycle back to their positionswhich result in the recording of charge sequence number 1. If thesubscriber employs the unauthorized card for several programs and thenuses the authorized card for one or more programs and turns in theauthorized card to the operating company for billing purposes, it caneasily be determined that a bootleg card has been employed. This, ofcourse, can be detected since the first charge sequence number recordedon the authorized card should be charge number 18 and this will not bethe case inasmuch as the charge sequence numbers starting at 18 areregistered on the counterfeit card.

The charge register thus records on removable code card 57 separatecharges (in the form of a pattern of one or more perforations) eachrepresenting a charge sequence number as well as the identity of aparticular one of the selected programs to which the subscribersubscribes. Each recorded charge has one characteristic (its positionalong the length dimension of the card) to indicate programidentification and another characteristic (the binary representation)denoting the charge sequence number, both of the characteristicschanging from one program to the next.

Punching out holes by means of piercing pins 169 to register chargesvery adequately accomplishes the objectives sought. As is the case withmost punching or piercing devices, however, chad (cut out portions)results. Of course, it is desirable that the chad not foul up theoperation of the charge register. Chadless type punches are available.but they have the disadvantage that it is sometimes difiicult to readilydetect the holes punched. Two variations of the charge register areshown in FIGURES 14-17 in each of which readily discernible holes arepierced in a recording medium without producing any undesirable chad.

The modified charge register shown in FIGURES 14 and 15 includes many ofthe elements previously de scribed, as indicated by the like referencenumerals. Instead of using a series of movable bellcranks and lancingpins, the function of piercing holes in a recording medium is performedby a series of five thermal devices or heating elements 191 mounted in afixed position within stator support 93 in approximately the samepositions occupied by channels 172. One terminal of each heating element191 is connected via a conductor 192 to a terminal of a source ofenergizing potential (not shown) and the other terminal of each thermaldevice is connected by a conductor 193 to an assigned respective one ofa series of five metallic electrically conductive sensing elements 194which are mounted to but insulated from bracket 121. Each of the sensingelements 194 lines up with an assigned one of the five discs 132. Thesediscs are made of some appropriate electrically conductive metallicmaterial in order that they may be constantly established at a groundpotential through the other metallic members of the apparatus actuatedby solenoid 149. The terminal of the energizing potential source whichis not connected to each conductor 192 is grounded.

In response to energization of the solenoid and movement toward theright of each of the five discs 132 certain ones of the sensing arms 194will be grounded, as determined by the portions of the discs adjacentthe sensing arms. In other words, if a disc 132 has an unnotched orraised section adjacent the free end of the associated sensing arm 194,that arm will engage the raised portion and establish an electricalconnection to ground. Grounding of a conductor 193 completes theenergizing circuit for the associated thermal device 191, causing thatdevice to heat a localized area of code card 57. Of course, card 57should be heat sensitive in order that energization of heating element191 beats the area of the card in juxtaposition with the heating elementto the extent that an aperture is actually produced or burned out ofcode card 57.

As a consequence, the heat piercing arrangement of FIGURES 14 and 15facilitates the recording of separate charges for each program in theform of holes, as in the case of FIGURES 2-13, which represent programidentification and charge sequence. However, there is no chad. Moreover,the system of FIGURES 14 and 15 requires fewer movable parts than thatof the first described arrangement. Specifically, the function performedby movable pins 169 and bellcranks 162 is served by fixed elements 194and 191.

In brief, FIGURES 14 and 15 illustrate recording apparatus forregistering information on a heat sensitive recording medium 57. Eachthermal device 191 responds to a predetermined energization forselectively heating a localized area of the recording medium.

Burning perforations in card 57 has the disadvantage that ash may resultalong with fumes which may conceivably contaminate electrical contactswithin the subscription television receiver. Such a disadvantage iseliminated by means of the laminated strip 198 shown in FIG- URES 16 and17 and which is adapted to be used in the charge register shown byFIGURES 14 and 15. The recording medium itself takes the form of a thinfilm or sheet of prestressed, heat-shrinkable material 196, such aspolyethylene. The heat-shrinkable material 196 is flaccid and laminatedbetween two self-supporting laminations 197 which may be made ofcardboard.

The left half of laminated strip 198, as viewed in FIG- URE 16, includesperforations that extend through all three laminations or layers andcorrespond to perforations 61 of the code card of FIGURE 8. In the righthalf of strip 198 aligned holes are precut or prepunched in bothlaminations 197 and these apertures are positioned so that they will beselectively placed in juxtaposi- 16 tion with the five heating elements191. Before any recording occurs, thin film 196 of heat-shrinkablematerial is continuous and extends across all of the perforationsprepunched in laminations 197. Whenever an area of film 196, defined bya pair of aligned perforations in lamination 197, is heated by a heatingdevice 191 an aperture will be developed in that area.

Specifically, heat from the thermal device 191 causes the thin film 196to open since the molecules in the thin film are under stress and wouldbe permitted to relax. The flow in the thin film would thereby cause anopening. However, no ash or fumes are produced. Reference numbers 199designate the areas of thin film 196 that have been heat pierced. All ofthe blackened or filled in circules in the right half of card 198 inFIGURE 16 illustrate localized areas of film 196, exposed through theprepunched apertures of the top lamination 197, that have not beensubjected to the restricted-area heating of a thermal device 191.

Laminations 197 not only serve as a support for flaccid thin film 196,but in addition the prepunched perforations in the laminations confinethe size of the apertures produced by the heating elements. Thelaminations provide a heat shield to prevent undue enlargement of asingle hole.

Hence, thin film 196 provides a recording medium including a thin sheetof pre-stressed, heat-shrinkable material predetermined localized areasof which are adapted to be placed, one at a time, in juxtaposition withthe restricted-area heating elements 191. Laminations 197 maintainportions of recording medium 196, outside the predetermined areas, infixed space relation with the heating elements. Energization of theheating elements 191 produce apertures in heat-shrinkable material 196Within the predetermined areas.

Certain features described in the present application are disclosed andclaimed in the following copending applications filed concurrentlyherewith: Ser. Nos. 468,486, in the name of Pentti V. Sarlund; 468,493,in the name of James C. Gaudio; and 468,492, in the name of Erwin M.Roschke, and which issued May 9, 1967 as Patent No. 3,319,257, all ofwhich are assigned to the present assignee.

While a particular embodiment of the invention has been shown anddescribed, modifications may be made, and it is intended in the appendedclaims to cover all such modifications as may fall within the truespirit and scope of the invention.

I claim:

1. A switching apparatus comprising:

a first set of switch contacts having a multiplicity of notches arrangedin a series of parallel rows;

a second set of switch contacts having a multiplicity of bearing ballsarranged in a series of parallel columns extending across said rows withthe bearing balls of each column disposed in alignment with and springurged toward assigned respective ones of said notches;

a multi-position, perforated insulating strip adjustably supportedbetween said first and second sets of contacts and in each positioninterposing a preselected pattern of perforations between said bearingballs and said notches permit only predetermined ones of said bearingballs to engage their assigned notches through the perforations andpermutably connect to said first and second sets of switch contacts; and

means for selectively moving said strip from one position to another tochange the permutation pattern between said first and second sets ofcontacts.

2. A switching apparatus comprising:

a first set of switch contacts, each having a plurality of notches,arranged in rows;

a second set of switch contacts, each having a plurality of alignedbearing balls spring urged toward assigned respective ones of saidnotches, arranged in columns;

a multi-position, perforated insulating strip adjustably means forselectively moving said strip from one position to another to change thepermutation pattern between sald first and second sets of contacts.

3. A switching apparatus comprising: a first set of switch contactsarranged in rows and each having a plurality of notches;

second set of switch contacts arranged in columns which areperpendicular to said rows and each having a plurality of alignedbearing balls spring urged toward assigned respective ones of saidnotches; perforated insulating member separating said first and secondsets of contacts; and

means for effecting relative movement of said insulating member withrespect to one of said sets of contacts from one to another of amultiplicity of different positions, in each of which positions adifferent and unique pattern of perforations is interposed between saidbearing balls and said notches to permit only predetermined ones of saidbearing balls to engage their assigned notches through the perforationsand permutably connect said first and second sets of switch contacts.

A switching apparatus comprising:

rotor assembly including a plurality of parallel arcuate first switchcontacts arranged in a series of parallel rows and each having a seriesof notches with said first switch contacts oriented so thatcorresponding notches thereof are aligned in an axially extendingdirection;

stator assembly including a plurality of parallel second switch contactsarranged in parallel columns each having a plurality of aligned bearingballs spring urged toward assigned respective ones of said notches, withthe bearing balls of each column being coplanar with an assigned groupof corresponding notches;

perforated insulating member adjustably supported between said first andsecond contacts; and

means for concurrently moving said insulating member and said rotorassembly from one to another of a multiplicity of different positions,in each of which positions a preselected pattern of perforations isinterposed between said said bearing balls, and said notches to permitonly predetermined ones of said bearing balls to engage their assignednotches through the perforations and permutably connect said first andsecond switch contacts.

5. A switching apparatus comprising: a rotor assembly including a firstset of switch contacts arranged in rows and each having a series ofnotches; stator assembly including a second set of switch contactsarranged in columns and each having a plurality of aligned bearing ballsspring urged toward assigned respective ones of said notches;

a perforated insulating member separating said first and second sets ofcontacts; and

means for concurrently moving said insulating member 6. A switchingapparatus comprising: a first set of switch contacts, each having aseries of notches, arranged in rows;

a second set of switch contacts, each having a plurality of alignedbearing balls spring urged toward assigned respective ones of said firstset of switch contacts, arranged in columns;

a perforated insulating strip separating said first and second sets ofcontacts and mounted in a fixed and predetermined position with respectto said first set of switch contacts such that each perforationregister; with an assigned respective one of said notches; an

means for concurrently moving said first set of contacts and saidinsulating strip with respect to said second set of contacts from one toanother of a multiplicity of different positions, in each of whichpositions a different and unique pattern of perforations registers withsaid bearing balls to permit predetermined ones of said bearing balls toengage predetermined ones of said notches through the perforations andpermutably connect said first and second sets of switch contacts.

7. A switching apparatus comprising:

a first set of switch contacts arranged in rows and each including aconductive bus bar having a plurality of spaced apart notches;

a second set of switch contacts arranged in columns, perpendicular tosaid rows, and each including a conductive bus bar and a plurality ofbearing balls aligned on the bus bar and springurged toward assignedrespective ones of said notches;

a multi-position, perforated insulating strip adjustably supportedbetween said first and second sets of contacts and in each positioninterposing a different and unique pattern of perforations between saidbearing balls and said notches to permit only predetermined ones of saidbearing balls to engage their assigned notches through the perforationsand permutably connect said first and second sets of switch contacts;and

means for moving said strip from one position to another to change thepermutation pattern between said first and second sets of contacts.

8. A switching apparatus comprising:

a rotor assembly including a set of switch contacts in the form of aseries of similarly shaped slip rings spaced apart and insulated fromeach other, each ring having a series of notches and with the notches ofeach slip ring aligned with the corresponding notches of the otherringsand in a direction parallel to the axis of said rotor assembly;

a stator assembly including a second set of switch contacts in the formofv a series of conductive bus bars parallel to each other and to theaxis of said rotor assembly, to each of which bus bars is electricallyconnected a series of bearing balls spring urged toward said slip rings;

a perforated insulating strip separating said bearing balls and saidslip rings and mounted in a fixed and indexed position with respect tosaid notches such that each perforation registers with an assignedrespective one of said notches; and

means responsive to rotation of said rotor assembly for concurrentlymoving said strip from one to another of a multiplicity of differentpositions, in each of which positions a different and unique pattern ofperforations registers with said bearing balls to permit predeterminedones of said bearing balls to engage predetermined ones of said notchesthrough the perforations and permutably connect said first and secondsets of switch contacts.

9. A subscription television receiver wherein a series of code signalcomponents are permutably applied by way of adjustable switchingapparatus to a plurality of input circuits of a control mechanism todevelop a decoding signal having a code schedule determined in part bythe instantaneous setting of such switching apparatus and in part by acharacteristic of said code signal components, said adjustable switchingapparatus comprising:

a first set of switch contacts, each having a plurality of notches,arranged in rows;

a second set of switch contacts, each having a plurality of alignedbearing balls spring urged toward respective assigned ones of saidnotches, arranged in columns;

a multi-position, perforated insulating strip adjustably supportedbetween said first and second sets of contacts and in each positioninterposing a different and unique pattern of perforations between saidbearing balls and said notches to permit only predetermined ones of saidbearing balls to engage their assigned notches through the perforationsand permutably connect said first and second sets of switch contacts;

means, controlled by the subscriber, for moving said strip from oneposition to another to change the permutation pattern between said firstand second sets of contacts; and

means for effectively indicating the pattern of perforationsinstantaneously interposed between said hearing balls and said notches.

10. A switching apparatus comprising:

a first set of switch contacts arranged in rows and each including aconductive bus bar having a plurality of notches, with each notch ofsubstantally the same width and having two relatively sharp edges;

a second set of switch contacts arranged in columns and each having aplurality of similar bearing balls, the diameter of each of which isgreater than the width of each notch, spring urged toward assignedrespective ones of said notches;

a multi-position, perforated insulating strip adjustably supportedbetween said first and second sets of contacts and in each positioninterposing a preselected pattern of perforations between said bearingballs and said notches to permit only predetermined ones of said bearingballs to engage the relatively sharp edges of their assigned notchesthrough the perforations to provide knife-edge electrical connectionsand permutably connect said first and second sets of switch contacts;and

means for selectively moving said strip from one position to another tochange the permutation pattern between said first and second sets ofcontacts.

11. A swiching apparatus comprising:

a first set of switch contacts arranged in rows and each having aplurality of notches of predetermined width;

a second set of switch contacts arranged in columns and each having aplurality of similar bearing balls, the diameter of each of which isgreater than the width of each notch, spring urged toward assignedrespective ones of said notches;

a perforated insulating strip separating said first and second sets ofcontacts, with each perforation having at least one dimension thatexceeds the diameter of each of said bearing balls;

means for mounting said insulating strip in a fixed and indexed positionwith respect to said first set of switch contacts such that eachperforation registers with and embraces an assigned respective one ofsaid notches; and

means for concurrently moving said first set of contacts and saidinsulating strip with respect to said second set of contacts from one toanother of a multiplicity of different positions, in each of whichpositions a different and unique pattern of perforations registers withsaid bearing balls to permit predetermined ones of said bearing balls toengage predetermined ones of said notches through the perforations andpermutably connect said first and second sets of switch contacts.

12. A switching apparatus comprising:

a first set of switch contacts arranged in rows and each including aconductive bus bar having a plurality of notches of predetermined width;

a second set of switch contacts arranged in columns and each having aplurality of similar bearing balls, the diameter of each of which isgreater than the width of each notch, spring urged toward assignedrespective ones of said notches;

a multi-position, perforated insulating strip separating said first andsecond sets of contacts and in each position interposing a different andunique pattern of perforations between said bearing balls and saidnotches to permit only predetermined ones of said bearing balls to fallinto and engage their assigned notches through the perforations andpermutably connect said first and second sets of switch contacts, thenotch width restricting the extent to which said predetermined bearingballs drop into their assigned notches such that the centers of saidpredetermined bearing balls lie above the notches; and

means for concurrently moving said strip and said first set of contactsfrom one position to another to change the permutation pattern betweensaid first and second sets of contacts, said predetermined bearing ballsbeing expelled from their assigned notches responsive to movement ofsaid first set of contacts.

References Cited UNITED STATES PATENTS 3,002,061 9/1961 Perkins 200-463,164,692 1/1965 Leuenberger 200-46 3,340,385 9/1967 Jonker 23561.11

RICHARD MURRAY, Primary Examiner H. W. BRITTON, Assistant Examiner U.S.Cl. X.R.

